Heat-treating machine



March 18, 1930. w. A. DRRAH I 1,750,924

HEAT TREATING MACHINE- f Filed June 4, 1927 64 Z7 Zd Figure J. v nvetar.

Patentedl Mahr. 18, 193() UNITED STATES l WILLIAM A. DARRAH,

l if 1.750,924

PATENT OFFICE F CHICAGO, ILLINOISv HEAT-'manucure MACHINE Application filed June '4,

this equipment may be useful wherever it is desired to controllably and uniformly heat. any substance to a specific temperatureand maintain it at that temperature for an appreciable time. i Referring to the drawing:

Fig. l shows a vertical side elevation in section of oneform of my device;

Figure II shows a top plan view partly in section of the same equlpment;

Fig. IH shows a horlzontal section along the line AA; v ,:fWhile Fig. IV shows an end elevation of the device illustrated in Fig. I; v Fig. IV is shown partlyin section; y '25 Fig. V shows another horizontal section of the device the section in -thiscase being taken along line BB; Fig. VI shows a detail of one form of basket which may ,conveniently be used with this equipment. f'i'j The equipment consists of a frame or spider (1) supported at its upper portion on a flange or rim (2) provided with a circular groove (3) arranged to roll over a series of balls (4), a coacting circular member (5) is located beneath the balls (4) and serves as a runway or track to confine them. A series of teeth or the equivalent (6) is provided in flange (2) and arran ed to engage with a driving memmay be driven from pulley (9) or by any other desired means. 'Shaft (8) is shown turninginbea-ring (10) which is su ported by bracket v(11) attached to the outsi e frameor housin (1 2).

The 'ousing (12) incluses an insulation or semi-refractory material (13) which is molded in-such a manner as to provide a series of iiues for purposes .later to be described. Inoue portion ofthe refractory ma- Vwith a discharge flue ber (7) w ich is mounted on shaft (8) and 1927. Serial No. 196,584.

terial (13) is molded a container or housing (14) containing a fan' wheel (15) which may be driven in any desired manner as for eX- ample by motor (16). A- flue portion (17) terminating near the 55 intake of fan (15) serves to deliver circulatl ing gases to the fan chamber (14). The operation of the fan forces these gases out through y outlet (18).

In the course of their travel thegases pass through a constriction or Venturi throat (19) and then Ato distributing duct (20). Distributing duct (20) is arranged to deliver cirr'culating gases in such a manner that they travel substantially horizontally throu h the spider member (1) and also through a asket member (21) which is carried by said -spider member (1). rlhe basket` member (21) is preferably made from perforated or exanded material or mesh in such a manner that it will hold the articlesbeing treated without allowing them to fall out, but will at the same time permit the ready passage of the circulating gases through the basket and into Contact with the material being treated. After passing through the material being treated the circulating gases leave by duct (22) which, connects to flue (23) which in turn delivers the gases to flue (17) and thus to the intake of the circulating fan or blower.

The arrows shown the direction of travel of the circulating gases which it will be noted is continuous in a single direction and of substantially constant volume `depending upon the resistance interposed in their path.

vA combustion chamber (24') constructed of proper heat resisting materials is located convement to the circulating gases and provided 25) leading to the throat or constriction oy venturi (19). An 90 alternative tlue connection (26) is shown by the dotted lines as leading from the discharge chamber to the intake of the fan (17 ).A Ob viously under ordinary conditions either iiue (25) or ilue (26) would be employed'and the 9" one not employed would be closed. a Ceftain advantages result from the use of each as will later be described.

Burners (27) and (28) are provided to deliver fuel to the comblyistion chamber. The 10 vio i Ai

`fuel may be gas, oil or the desired equivalent.

The burnersl may be controlled by thermo-` statlc valve 29). preferably operated from a thermostat 30) inserted in the discharge passage of the circulating gas. Thermostat (30) serves to maintain the temperature of the gas leaving the 4"circulatingfan at any desired constant value.

The housin (12) is .to beprovidedwith .a cover v(31). w ich may be operated in any 4desired manner as for example, by handle (.32) pivoted on bearin (33) and provided with counterweight (34 to permit easy adjustment. In theI course of operation of this device, it will be apparent that. when motor (16) is started in rotation a continuous circulation' of gases will take place as described following the gleneral direction of the arrows. When the urners (27) and (28) in combustion chamber (24) are lighted, it -will be Y. of the blower noted that the products of combustion arev drawn into the circulating gases either by the reduced lpressure resulting from the Venturi throat (19) or through the intake (17) passing in this case through Hue (26).

lt will be noted that when the' products of combustion travel through flue (26) into Atlie intake of the blower the blower will beffa@ quired to handle' circulating gases. at

. maximum temperature of th aevicawtii" onthe other hand, if the products of combustion pass 'through flue (25)'v instead of through iue (26) the blower will be required to handle circulating gases at the minimum gases when' they or returned temperature.

An exhaust flue (35) providedwith a selfclosing valve (36) provides ortlie discharge of excess gases, thus preventing* an accumulation of pressure in the system owing to' the ontinual additionof products of combus- It v ll be evident that thermostat '(30) `will regulate the-quantity@ fuel supplied by burners 27) `and" (28) thusinsuring a-con` stantuni ormtemperature o'f the circulatin pass through basket, (21g and into contact lwith the material therein.v

It will also beY a parent from the descri tion given l that asv asket (21).,is rotated y' nism .previously describe Veilcency may be ment.

means of spider member (1) andthe mecha- Y y al1 parts will be continuously sub 'ectd to substantially uniform treatment y'thefhotA blast of cirou latin .gas l distri ution offbeat throughout t e g, thus giving a highl `fi'inifor'my mass ofv material withinthe basket.

"Owing to the fact that the products of .oombustion are directly retainedPand mixedwith the`- circulating gases vev degrees of secure .wit this equip# A It Y will be apparent that e many-Iv obvioussubstitutonsnnay be made without departing drying cooking, boiling, melting, etc., as obviously e AIintend to 'indicate the space or-inclofollowsz from the s irit of this invention. For example, the asket may be constructed in any form or shape or in place ofthe basket I may employ a horizontal tube or I may prefer to allow the basket to remain stationary and depend on the movement of the air only, which Ii-havev found gives quite satisfactory results in many cases.

Obviously the Lbasket f' may be supported from a plate placed beneath it or in any other desired manner without departing from' the spirit of this invention.

I have found in actual practice that equipment of this kind will serve to heat articles to the desired temperature'with great accuracy and uniformity. ThatV is to say bylt will also be apparent that since the i products of combustion are held in the circu- ,lating gases and therefore'come in contact with the substances being heated, the ellif ciency must be very high.

ln referring to a-.heat treating machine, I

accomplish a useful result. Thus I intendl the term to coversuch operations as roasting, baking, annealing, carburizing,

this equipment will nd a wide field of application wherever a uniform and controlled temperature is required.

wish. it to be understood that am ,referring While I have shown a specific type of gash moving mechanism or blower, `it will be understood that anysatisfactory mechanism,

which vwill keep the gases in motion may be used. 4 Further I do not wish to be-restricted to'anyyparticular shape or design ofv con- .A

cases the container may be closed'aspfor example in .heatingv' ve .-'small'gjarticles .or

surelwliere ,the combustion'takes place oi' the vroduct's Vof combustion are concentrated.- i

fullydescribedmy invention what Ic aim as newandwish to securefby .Y ,1. y T-isa for heat treat' consistin'g'of 1 portfor slldiicontainer, a

avin now Letters `'Patent in the States, is. as

'y L1A-device a container, a fsu f `tainer as this will obviousl be varied to suit f the operations being carried out. In some circulating device, a combustion chamber,

means for conductingthe products of comrtainer, a mechanism for movin bustion from said combustion chamber into said gas circulation system at a position on the discharge side of said gas circulating device, and an exhaust outlet for permitting the escape of an excess ofcirculating gases, said exhaust openin being located on the discharge siderof sai gas circulating device.

2. A heat treating machine comprising a container, supporting means for saidrconsaid container, a complete gas. circulating system passing from a gas moving Vmechanism through said container and back to said gas movin mechanism, a combustion chamber, anda ue connecting said combustion chamber with a portion of the discharge of said gas moving mechanism, at a point of reduced sectional area.

3. A heattreatingv machine comprising a container, a support -for said container, a gas movin mechanism, a flue leading to said container rom said gas moving mechanism, a combustion chamber, and a flue making connection between said combustion chamber `and the discharge ue connecting said gas moving mechanism and said container, said connection being at a point o reduced sectional area in said first mentioned lue.

' 4. A heat treating machine comprisinga container, a sup ort for said container, a gasy moving mechanism, a flue leading J.from the discharge portion of said gas moving mechanism to said container, a iue leading from said container to the intake of said gas moving mechanism, a combustion chamber, saidl discharge flue from said gas moving mechanism having a constricted portion, and a connection between said combustion chamber chamber an said discharge of said gas moving mechanism.

6. A heat treating machine comprising a container, means for moving said container, a gas moving mechanism, a combustion chamber, lues connecting said container,I with said gas moving mechanism and sald v combustion chamber with 'the discharge of said gas moving mechanism and an exhaust means YA:for the escape voi excess gases.

from said gas movin -mechanism, a combus- -tion chamber and a ue connecting said cmbustion chamber to the discharge portion of said gas moving mechanism.

8. In a heating device a combustion chamber, a gas moving mechanism, and a chamber to be heated, liues connectin said chamber to be heated and said gas moving mechanism,

mechanism having a discharge portion of` varying cross section to form a venturi a combustion chamber and a connectionV e-f tween said combustion chamber and the reduced pressure portion of said venturi, and an exhaust outlet connected to the discharge portion of said gas moving mechanism.

11. in a heating machine, a chamber to be heated, a gas moving mechanism having a discharge portion of varying cross section to form a venturi, connected to said chamber to be heated, a combustion chamber and a connection between said combustion chamber and the reduced pressure portion of said venturi.

12. in a heating machine. a chamber to be heated, a gas movingmechanism having a discharge portion of varying cross section to form a venturi, acombustion chamber and a connection between said combustion chamber and the Yreduced pressure portion of said venturi, a connection between the .discharge of said venturi and said chamber to be heated, and a connection :between said chamber v .7. A.. heat treating machine comprising a I container, a support for said'contamer, a as fnf l moving. mechamsm,a Hue of varying e ec- 65' tive r tlr'rfisssection leay 1g' to said container 

